Cardiology/Angiology Flashcards
Atrial cardiomyocytes release __________________________ when stretched (i.e., at higher BPs) → ↑ water and sodium excretion by the kidneys → ↓ BP
atrial natriuretic peptide (ANP)
Why does damaged myocardial tissue eventaually lead to increased risk of cardiac arrythmias.
Damaged myocardial tissue is replaced by noncontractile scar tissue (fibrosis) that does not conduct electrical impulses well and, thus, predisposes to cardiac arrhythmias.
Why might pericarditis result in left neck/arm/shoulder pain?
Because of the sensory innervation of the pericardium by the phrenic nerve, pericarditis can result in referred pain to the neck, arms, or shoulders (often the left side).
What nerve provides sensory innervation to the pericardium?
The phrenic
Why is it difficult to treat endocarditis involving the valves?
The valves are mostly vessel-free, with nutrition derived from the surrounding blood This makes valvular involvement in endocarditis difficult to treat because both the cells of the immune system and antibiotics typically reach sites of infection via the circulatory system.
What major tissue in embyology does the heart originiate from?
All three major layers of the heart orginiate from the mesoderm
Valve located between right atrium and right ventricle
Tricuspid (Consists of three leaflets)
Valve located between left atrium and ventricle
Mitral valve/Biscuspid Valve
When do the coronary arteries fill with blood?
The coronary arteries fill with blood during diastole because they are compressed during ventricular systole.
Most commonly occluded coronary artery
The LAD is the most commonly occluded coronary artery and is often referred to as the “widow maker” due to the high mortality rate associated with LAD infarction.
What coronary artery has a propensity to increase cardiac arruthmia w/ooclusion?
The RCA usually supplies the heart’s conduction system (sinus and AV node) so that stenosis or occlusion of this vessel often leads to cardiac arrhythmias.
Chronotropy
The ability to influence heart rate. Positively chronotropic drugs (e.g., adrenaline) increase heart rate, while negatively chronotropic drugs (e.g., beta blockers) decrease heart rate.
Inotropy
The ability to influence the force of cardiac muscle contraction. Positively inotropic drugs (e.g., catecholamines) increase the force of contraction, while negatively inotropic drugs (e.g., beta blockers) decrease the force of contraction.
Dromotropy
The ability to influence the conductivity of cardiac tissue. Positively dromotropic drugs (e.g., catecholamines) increase the rate of conduction of an electrical impulse through cardiac tissue, while negatively dromotropic drugs (e.g., digoxin) decrease the rate of conduction of an electrical impulse through cardiac tissue.
What are the layers of the heart?
Endocardium
Myocardium
Epicardium: connective tissue layer attached to the outside of the myocardium, i.e., visceral layer of serous pericardium
Pericardium: membrane that directly surrounds the heart
What is the frank starling law/principle?
A principle that describes the relationship between end-diastolic volume and cardiac stroke volume. Cardiac contractility is directly related to the wall tension of the myocardium; an increase in end-diastolic volume will cause the myocardium to stretch, which increases contractility and results in increased stroke volume.
What is stroke volume?
Volume of blood pumped by the left or right ventricle in a single heartbeat
SV = end-diastolic volume (EDV) − end-systolic volume (ESV)
How do you calculate stroke volume?
SV = end-diastolic volume (EDV) − end-systolic volume (ESV)
What is ejection fraction?
Ejection fraction (EF): the proportion of EDV ejected from the ventricle
–> EF = SV / EDV = (EDV - ESV)/EDV
–> Normally 50–70%
What does ejection tell us?
Serves as an index of myocardial contractility: e.g., ↓ myocardial contractility → ↓ EF (seen in systolic heart failure, where EF is < 40%)
How does ejection fraction differ in systolic versus diastolic heart failure?
Systolic: EF is LOW
Diastolic: EF is NORMAL
the rate at which blood flows back to the heart, which typically equals cardiac output
venous return
How do you calculate cardiac output?
Cardiac output (CO) = heart rate (HR) × stroke volume (SV)
Fick principle
Cardiac output is proportional to the quotient of the total body oxygen consumption and the difference in oxygen content of arterial blood and mixed venous blood.
Cardiac output (CO) = oxygen consumption rate/arteriovenous oxygen difference = (O2 consumption)/(arterial O2content - venous O2 content)
